"The woman has the chocolate cake."
Translation:La donna ha la torta al cioccolato.
Most of the time : al = a + il = to the , at the
With food, "a" is used for flavorings and "di" for composition: "il gelato al caffè" is a coffee flavored ice-cream, "il gelato di soia" is the soy milk imitation, i.e. an ice-cream made of soy instead of cream. (by f.formica)
The question of whether to use masculine or feminine seems to be cleared up in this article - https://dailyitalianwords.com/?s=chocolate
Solid chocs are masculine and drinks are feminine and we really wouldn't want to get something as important as chocolate wrong :-)
I'm feeling hungry.